I am building a timber frame building for processing maple syrup. It is 16 x 24 with 8" x 8" beams. ( an expansion of Sobins garden shed in his book) I want a concrete floor to be able to spray down and clean up after each season. My contractor tells me that a Monolithic or floating slab foundation is fine for such a building frame. I am concerned with the stress points on the corners of the floor. He has indicated he will use re-rod and steel mesh to reinforce. Should I be concerned? I have a bid for a traditional 4' footing, but it is really expensive! Any advise would be appreciated. Thanks, Chris.

You should have your foundation/concrete floor re-enforced where the posts will sit.
Just adding re-bar and mesh near the corners and post locations may not be enough.

Welcome to the Forum!

Are you going to have a monitor roof on your suger house? Just today I had a discussion about building a monitor-roofed sugar shack on a slab. I've heard of slabs being poured much thicker at the outside and tapering up in the center. I'm not sure if that's an Alaskan slab or not.

My nderstanding is that the perimeter of the foundation is 16" deep and 10" wide tapered back to 5" within 2 feet of the edge all around the perimeter. Rebar is then placed in the edge. I am not sure what a monitot roof is? I will have a louvered opening in the roof for steam release.

Hey there,

I for one am not a big fan of building anything in the northern part of this country (USA) on any sort of slab, unless it is a small stick framed garage that no one cares about.

One way to support the frame and still be below the frost line is to set the sill beams on top of buried treated posts which in turn rest on concrete footings called cookies. Treated posts are placed below grade, and the sill sits just above final grade.

The concrete floor can then be poured inside the building, between the sill beams. Expansion boards can be added to the inside sufaces before the floor is poured,... this way the floor can "float" without heaving the building.

A couple things to think about is that woodchucks and rats love slabs!....
and the sills could also be cut out of preasure treated SYP utility poles since they will be in contact with the ground and the concrete/ water.

Good Luck,

Rooster

Hi Chris,

do you have 8x8 timber sills?

If so, I think the slab you describe in your second post should be fine, provided it sits on well drained material(3/4 stone for example).
Most of the trouble I see with slabs in my area is that the site is not drained, so water is able to get under the slab and freeze, which will shift or break the slab.

Just have him dig a 4x4 or so hole or pit where each post will sit. Then have him make a rebar cage to put in the hole. The just fill it with concrete when you pour your footings.

I was planning on using 8" x 8" timber sills. Thanks for the response!

I would not hesitate to use such a slab as stated. As additional protection a protective layer of 2" foam around the perimeter, laid flat, and extending 2' away from the building, 4' would be better and the experts engineer call for 6'. The soil should be well drained. If you have a soil which retains a lot of water or the site is wet, a slab is not the best bet. Drainage will be important. Gutters help control water flow. If you get lots of snow this helps insulate the ground as well. I would refrain from plowing near the sides of the building, as this surface would be exposed to night time radiation and more frost build up.

I have two building a 30'x60' and a 28x36' both on slabs with less thickness on the edges than mentioned and they are functioning well, and no insulation around the edges. One will receive the foam around the edge this fall, it has been in service for near 10 years now and we are about to move in.

One has 8x8 sills, the other a 2x10 plate.

Tim